disable external display in mountain lion

Question

Level 1

0 points

disable external display in mountain lion

Hi

I haven an iMac 27" with Mountain Lion. Im using it for work with a Dell monitor as external display - extending my desktop to the right.

The problem is, when I turn off the Dell, the iMac still detect it - and keep my desktop extented, leaving various apps off screen (ex. safari) . I have to physically unplug the Dell from my iMac, before it "resets" to normal.

On my laptop its possible to switch between - laptop screen only, both screens duplicated, both screen extended - Using keyboard shortcuts

Is it possible to do this on my iMac in some way ?

// Thomas

iMac (27-inch Mid 2010), OS X Mountain Lion

Posted on Aug 9, 2012 1:21 PM

Reply

Answer 1

captfred

Level 7

26,422 points

Aug 9, 2012 1:31 PM in response to ThomasKugle

Not sure if this is what you're asking but,

CMD F1 will toggle between mirror mode and extended mode.

Reply

Answer 2

ThomasKugle Author

Level 1

0 points

Aug 9, 2012 1:49 PM in response to captfred

Not completly.

Im looking for way to toggle between enable and disable external display.

So its:

option a = Only using my iMac display

option b = Using both my iMac display and my Dell monitor.

I would have thought it was enough to turn off the Dell monitor, but it isnt.

Reply

Answer 3

ThomasKugle Author

Level 1

0 points

Aug 27, 2012 1:57 PM in response to ThomasKugle

Anyone ?

Its a bit retardet if you can't turn extended mode, without unplugging the cable.

Reply

Answer 4

marchede

Level 1

0 points

Nov 3, 2013 3:37 AM in response to ThomasKugle

I second: Anyone?

I've an external montor that I share as a TV, a secondary display of a Linux workstation, and a secondary display of iMac (don't have enough desk space for 4 monitors.)

If I use mirroring, I only get the resolution of the monitor, not the original iMac resolution.

I'm not inclined to disconnect the little displayport connector on the back of my iMac everytime (hard to reach without standing up, and it hurts my wrist to try to connect to that little port.) I tried Shade software and it didn't work. I haven't tried Switchresx because I don't want to shell out $18 for just disabling a monitor.

I can share my keyboard+mouse using software (synergy) but I can't disable my monitor using software? That's just not right.

Reply

Answer 5

Apr 8, 2014 1:23 AM in response to ThomasKugle

Another one expecting some workaround...

I thought that a reasonable answer could be mirroring the main screen so you don't lose cpu/gpu resources nor the desktop is extended, that way I guess the major drawbacks of having both monitors enabled are gone. Only remains the fact that the external monitor is still working which you can fix simply by selecting another input or turning it off.

BUT, as marchede stated, switching to mirror mode lowers you the imac resolution to the external monitor's.

Does anybody know a way to use mirroring without adapting to external monitor resolution?

Reply